1. Field
The presently disclosed embodiments relate generally to the field of disk drives, and more specifically to a disk drive for storing multi-media data objects.
2. Background
There is a growing demand for storage of multi-media data objects such as movies, music, games, books, texts, graphics, and interactive programming. Known devices for storing large multi-media data objects comprise disk drives designed to read and write at the same speed. Disk drives that read and write at the same speed were designed for computer applications, where it is important to both read and write quickly, and where each disk access operation has an equal probability of being a read operation or a write operation. Requirements for multi-media object storage and retrieval are different than requirements for storing computer applications.
The use of a standard disk drive, in storing video for example, renders disk drive access that is faster than necessary when reading, and slower than necessary when writing. Because the disk platter spins faster than necessary when performing read operations for video playback, the disk drive consumes more power than necessary during video playback. For portable video playback devices, it is desirable to reduce power consumption during playback, requiring the disk to spin just fast enough so that data is produced at a rate required to drive a real-time video or multimedia stream. A typical rate for driving a real-time video or multi-media stream could be 5 Megabits per second (Mb/s). A disk drive operating at 5 Mb/s does not allow writing at a desired rate for storing large multi-media data objects in a short period of time. A desired write speed for storing a large multi-media data object in a few minutes could be 250 Mb/s, or approximately 50 times faster than the desired speed for reading.
Disk drives known in the art spin at one constant speed. Common speeds are 5400 revolutions per minute (rpm), 7200 rpm, 10,000 rpm and 15,000 rpm. Very small disk drives may spin slower, at approximately 3600 rpm. Thus, there is a need in the art for a disk drive with multiple modes of operation to provide individually selectable read and write speeds for storing and retrieving multi-media data objects.
Embodiments disclosed herein address the above-stated needs by providing a variable mode multi-media data object storage device with at least two modes of disk drive operation supporting different platter rotation speeds and head configurations for reading and writing.
Accordingly, in one aspect of the invention, a storage device includes a disk drive configured to operate at either a first rotation speed or a second rotation speed, and a processor coupled to the disk drive and configured to control the disk drive to operate at either the first rotation speed or the second rotation speed.
In another aspect, a disk drive for storing multi-media data objects includes a magnetic disk, at least one individually selectable disk speed for reading, at least one individually selectable disk speed for writing, wherein the disk speed for writing is faster than the disk speed for reading, a plurality of write heads for writing multi-media object data to the disk, and one read head for reading multi-media object data from the disk.
In another aspect, a variable mode disk drive for storing multi-media data objects operating in at least one read mode and at least one write mode includes a bus interface for providing input data to a buffer while the disk drive operates in a write mode, and for transferring output data from the buffer while the disk drive operates in a read mode, a slider mechanism for positioning one read head and a plurality of write heads over a magnetic disk, read and write electronics for processing data for transfer to and from the magnetic disk, and a processor for controlling the rotation speed of the magnetic disk.
In another aspect, a method for storing data on a disk drive includes configuring the disk drive to operate at a first rotation speed for reading, and configuring the disk drive to operate at a second rotation speed for writing, wherein the rotation speed for writing is faster than the rotation speed for reading.
In another aspect, a method for storing data to a disk drive having at least one disk speed for reading and at least one disk speed for writing, wherein the speed for writing is faster than the speed for reading, includes receiving data from a bus interface, processing the received data for simultaneous writing to the disk by a plurality of write heads, rotating the disk drive at the faster speed for writing, and writing the processed data to the disk by simultaneously using a plurality of write heads.
In yet another aspect, a method for retrieving data from a disk drive having at least one disk speed for reading and at least one disk speed for writing, wherein the speed for writing is faster than the speed for reading, includes rotating the disk drive at the slower speed for reading, reading data from the disk drive, processing the data to create a multi-media data stream, and providing the data stream to a bus interface.